This invention relates to novel ultraviolet-emitting phosphors and to methods of preparation thereof.
Very little is known about inorganic cathodoluminescent materials which can emit at wavelengths shorter than 3000 A, and very few such phosphors are known. One such phosphor, disclosed in U.S. Pat. No. 2,770,749 to A. Bril et al, is a self-activated zirconium pyrophosphate phosphor (ZrP.sub.2 O.sub.7). This phosphor contains highly-charged zirconium ions with an np.sup.6 nd.sup.0 configuration. The emission is believed to come from the metal ions themselves through charge-transfer transitions between the O.sup.2 .sup.- anions and the central metal ion. No activators are needed for this process.